The invention relates generally to a rotor and hammer assembly with a removable hammer for use with a size reducing machine. More specifically, the invention relates to a rotor and hammer assembly comprising a drive shaft with a rotor casing sealed by two end plates, and with a hammer removably secured to the outer surface of the rotor casing.
Impact crushers, like rotary hammermills or tub grinders, and the like, of the type contemplated herein, are widely used to size reduce objects into smaller fragments through rotation of a motor driven rotor. These devices typically include a plurality of hammers attached to the rotor. During operation the rotor spins allowing the hammers to impact, and thereby size reduce material.
Rotor assemblies used in conjunction with size reducing machine (such as tub grinders, rotary hammermills, vertical feed machines, and the like) experience a number of problems associated with the operation and maintenance of the size reducing machines. For example, the powerful and violent interaction between the rotor assembly and the matter being size reduced causes a great deal of wear on any exposed surfaces. Furthermore, the interaction between the material inside the machine and the rotor and hammer assembly is difficult to control in a manner that allows for smooth and efficient operation of the machine.
Further, prior art rotor assemblies utilize a complex arrangement of parts. The parts include a plurality of hammers secured in rows substantially parallel to a drive shaft. The hammers secure to a plurality of plates, wherein each plate orients about the drive shaft. The plates also contain a number of distally located holes. Pins, or rods, align through the holes in the plates and in the hammers. Additionally, spacers align between the plates. All these parts require careful and precise alignment relative to each other. In the case of disassembly for the purposes of repair and replacement of worn or damaged parts, the wear and tear causes considerable difficulty in realigning and reassembling of the rotor parts. Moreover, the parts of the rotor assembly are usually keyed to each other, or at least to the drive shaft, this further complicates the assembly and disassembly process. For example, the replacement of a single hammer can require disassembly of the entire rotor. Given the frequency at which wear parts require replacement, replacement and repairs constitute an extremely difficult and timeconsuming task that considerably reduces the operating time of the size reducing machine. In some cases removing a single damaged hammer can take in excess of five hours, due to both the rotor design and to the realignment difficulties related to the problems caused by impact of debris with the non-impact surfaces of the rotor assembly.
Prior art rotor assemblies expose a great deal of the surface area of the rotor parts to debris. The plates, the spacers, and hammers all receive considerable contact with the debris. This not only creates excessive wear, but contributes to realignment difficulties by bending and damaging the various parts caused by residual impact. Thus, after a period of operation, prior art rotor assemblies become even more difficult to disassemble and reassemble.
In addition, in many cases the size of the hammers and the attached hammer tips may vary based on the type of material processed in the size reducing machines. In this case, all of the hammers may need replacement to accommodate a different design or size, or to allow for attachment of a different size tip. Replacing even one hammer can take considerable time with prior art rotor designs, let alone all of the hammers.
Based on the foregoing, those of ordinary skill in the art will realize that a need exists for a hammer and rotor assembly that allows for replacing hammers in a manner that reduces the amount of maintenance, increases efficient operation, and better utilizes manpower and machine resources
Incorporated herein by reference are the following patents and/or patents applications, which contain material of relevance to the present invention: U.S. patent application Ser. No. 09/436,951 entitled PRODUCTION PLUS HAMMER WITH PROTECTIVE POCKET filed on Nov. 9, 1999, now U.S. Pat. No. 6,311,910; U.S. patent application No. 09/326,209 entitled SADDLE-BACK HAMMER TIP filed on Jun. 6, 1999, now U.S. Pat. No. 6,131,838 issued on Oct. 17, 2000; and U.S. patent application Ser. No. 09/666,360 entitled SADDLE-BACK HAMMER AND HAMMER TIP filed on Aug. 20, 2000.
An object of the present invention comprises providing a rotor and hammer assembly with a removable hammer for use with a size reducing machine.
These and other objects of the present invention will become apparent to those skilled in the art upon reference to the following specification, drawings, and claims.
The present invention intends to overcome the difficulties encountered heretofore. To that end, the invention comprises a rotor and hammer assembly comprising a drive shaft allowing for rotating the rotor and hammer assembly. End plates are secured to the drive shaft, and a rotor casing is secured to the end plates. The rotor casing has an outside surface, to which hammer is removably secured.